时空域共轭干涉复函数耦合的双波长干涉算法  

Dual-wavelength interferometric algorithm based on spatial-temporal conjugate complex function coupling

作　　者：成金龙 朱立砚[1] 陈露 杨忠明 高志山[4] 袁群 Cheng Jinlong;Zhu Liyan;Chen Lu;Yang Zhongming;Gao Zhishan;Yuan Qun(School of Physics and Electronic Electrical Engineering,Huaiyin Normal University,Huai'an 223300,China;Jiangsu Institute of Metrology,Nanjing 210023,China;School of Information Science and Engineering,Shandong University,Qingdao 266237,China;School of Electronic and Optical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]淮阴师范学院物理与电子电气工程学院,江苏淮安223300 [2]江苏省计量科学研究院,江苏南京210023 [3]山东大学信息科学与工程学院,山东青岛266237 [4]南京理工大学电子工程与光电技术学院,江苏南京210094

出　　处：《红外与激光工程》2024年第4期183-193,共11页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(62105116,62175107,62205148);江苏省高校2023年“青蓝工程”项目;江苏省高等学校基础科学(自然科学)研究面上项目(21KJB140004)。

摘　　要：为从双波长莫尔条纹中提取合成波长干涉信息以扩展测试量程,提出了时空域共轭干涉复函数耦合算法。利用干涉图间时域相移与空域载频的转换,低载频时分离频谱以获取时空域复函数,经共轭耦合提取合成波长干涉图,且不引入其他干涉信息。干涉图组内单波长π/2与组间合成波长π/2的双重移相策略,实现了合成波长干涉图提取后的直接解调。与传统空域傅里叶变换方法相比,考虑波长间相移偏差,算法所需载频数值仅为前者的0.077。仿真峰谷值为74.2 nm的波面在莫尔条纹包络数目为1时,恢复偏差峰谷值优于0.5569 nm。实验中,7.8μm高度台阶样品在低载频时,阶跃高度的相对误差仍优于0.94%。仿真与实验数据验证了算法的可行性,为实现双波长干涉中低频干涉信息的获取提供了新的思路。Objective Traditional single-wavelength interferometry is not suitable to unwrap the correct phase for measuring surface with step or groove,whose depth is larger than half wavelength.Dual-wavelength interferometry(DWI)technique employs an extra wavelength to generate a longer beat-frequency synthetic wavelength().For synthetic wavelength is much longer than the optical working wavelength,DWI extends the measuring discontinuity limit of interferometry greatly.And DWI could achieve the simultaneous accurate measurements with large dynamic range for the multi-scale morphology characteristics parameters such as the macro profile and local morphology with step.Meanwhile,in the simultaneous dual-wavelength interferometry(SDWI),the two single-wavelength interferogram is captured simultaneously to accelerate the data collection,which is immune to vibration with the advantages of the time saving and higher efficiency.In practice,the dualwavelength interferogram is usually captured by the monochrome sensor,which is more convenient and economical.And a generated dual-wavelength Moiréfringe pattern appears as the simple incoherent additive superposition of the two corresponding single-wavelength interferogram.The low beat-frequency envelope of the generated fringe pattern indirectly represents the needed synthetic-wavelength information,whose direct extraction is rather arduous.For this purpose,we present a dual-wavelength interferometric algorithm combining with spatial-temporal conjugate complex functions coupling and double phase shift strategy.Methods The method needs to acquire multiple groups of phase-shift dual-wavelength interferogram,and each group consists of four continuous interferogram.The phase shift step among the four frames in each group is required asπ/2 at one single wavelength,whileπ/2 at synthetic wavelength between the adjacent groups by the designed double phase shift strategy(Fig.2).And in dual-wavelength squeezing interferometry for each group,the temporal phase shift in each group is converted i

关 键 词：测量 干涉 傅里叶变换 双波长 莫尔条纹 

分 类 号：O439[机械工程—光学工程]